In Asian countries,
highly intensive agriculture has been popular since ancient times because of
high population density, limited area of arable land and rice cultivation.
Therefore, various traditional cultivation techniques had developed in order to
raise the productivity of crops. Any kinds of wastes, the excretions of human
and live stocks, straw, leaf litter, grassAsewages and
rice husk charcoal have been used as fertilizers and soil amendments, not only
in agriculture but also for gardening or revegetation. Wood ash containing some
cinders was especially used as an important material for soil amendment and
mineral supply.

In Japan where the domestic supply of energy sources has been limited,
the forest resources, fire wood and charcoal were most important energy
sources until the beginning of 20th century.
Charcoal production and consumption increased with the increase of population
and reached a maximum, 2.7 million ton per year in 1947. It has been estimated
that wood, mainly broad leaved trees, of about 10 million ton was carbonized by
traditional kiln at that time(1).

However, due to the rapid
increase of imported fossil fuels in the 1960s, the so called gFuel Revolutionh
occurred, and the production of charcoal decreased to a minimum of about 30
thousand ton per year in 1980s. The abrupt changes in peoplefs daily life and the
changed relationships between humans and forest caused the decrease of
Matsutake mushroom, mycorrhizal fungus production and the outbreak of pine
wilting disease (2).

Under such circumstances, late Dr. S. Kishimoto and G. Sugiura who were experts of charcoal and wood vinegar production began the movement to make revive charcoal and to encourage the new use of charcoal in 1970fs. In 1980 they published a book gIntroduction to charcoal making on Sundayh (3) and distributed the knowledge of popular charcoal making and use. They contributed considerably toward the present prosperity of the charcoal business in Japan and Asia.. The author, M. Ogawa and his colleagues began the studies on the utilization of charcoal in agriculture and forestry on their requests in 1980 and reported the effects of bark charcoal on soy bean and pine tree in 1983(4) (5).

Being
encouraged by the activities of Kishimoto, Sugiura and Ogawa and the extension
of organic farming in Japan, the application and studies of
charcoal in agriculture became active in 1980s. In 1986, the gTechnical
Research Association for Multiuse of Carbonized Materialsh (TRA) was
established by the financial support from the Japanese Forest Agency, and the
studies of new charcoal use launched with the participation of 13 private companies
for 3 years. The studies on the effects of charcoal and wood vinegar were
conducted covering various aspects; the improvement of carbonization technology,
soil amendment in agriculture and revegetation, activation of microorganisms
and water purification. The research results with some general comments were
published in 1990 and widely distributed (6).

Due to the report, the
effects of charcoal and wood vinegar were recognized in public and authorized as
a specific material for soil amendment by MAFF (Ministry of Agriculture,
Forestry and Fishery) in 1990. However, contrary to the
government expectation of increasing the charcoal production in rural area, the
cheaper charcoals have been imported from Southeast
Asia being produced from coconut and oil
palm shells and reached to the same level as domestic supply. In this paper,
only the publications written by Japanese researchers are introduced, because they
seem to be difficult to access in other countries. Also English in this paper
was checked by Dr. P. Blackwell so kindly.

1.Charcoal
Utilization in Agriculture and Gardening

1)Rice
husk charcoal

The oldest description on charcoal use in agriculture is found in a text
book, gNogyo Zensho (Encyclopedia of Agriculture)h written by Yasusada
Miyazaki in 1697 (7). He described in it; gAfter roasting every wastes, the dense excretions
should be mixed with it and stocked for a while. This manure is efficient
for the yields of any crops. It is called the ash manureh. Probably similar
knowledge had been popular in China and
Korea since ancient time.

In Asian countries, rice husk charcoal which can be carbonized by
simple methods in field soon after harvesting has been one of the most common
materials for soil amendment. It seems that rice husk charcoal has been used
for several thousand years since the beginning of rice cultivation in Asia,
because rice husk with high content of silica is decomposed a little in soil and
useless as a compost material.

The custom using rice husk charcoal mixed with excreta had been very
popular among farmers particularly in wheat cultivation until about 60 years
ago. There seemed to be reasonable benefits, because the charcoal can absorb
and keep chemical nutrients and deodorize the excreta. However, this method was
too popular to investigate for scientists. This led to the roles of charcoal in
agriculture being neglected for long time. After the information on wood charcoal
use was circulated in1980fs, the roles of rice husk charcoal were recognized
and investigated by agricultural researcher again.

For instance, recently Ezawa et al. (8) reported that rice husk and its charcoal enhanced A (arbuscular) mycorhiza
formation of some crop plants and improved soil physical properties when
each material was added top soil. Ishii et al. (9)also reported the same effects on the A mycorrhiza formation of citrus
seedlings. Komaki et al. (10) suggested that a small amount of rice husk charcoal could increase the
growth of Catharanthus roseus, but the browning of leaves appeared with
the excessive application because of high concentration of potassium and
higher pH of rice husk charcoal than wood charcoal. Takagi et al. (11)proposed a practical method to reduce the outflow of
pesticides and herbicides from paddy field utilizing the absorbing ability of
rice husk charcoal. Also he tried to fix the bacteria with high decomposing
ability of pesticide into rice husk charcoal and succeeded to reduce the
outflow of herbicide simazine from a golf course (12).

@At present, carbonizing
methods have developed from the traditional kiln to the sophisticated facilities
equipped at rice mill. Dried rice husk can be carbonized automatically and
continuously in a self-fuel kiln and the extra heat is utilized for small scale
power generation (13). Recently the facility
and system has been exported to South East
Asia by Kansai Sangyo Co. Ltd. It is probably possible to apply this automatic carbonization technology to wheat and barley chaff and other crop plant residues.

In Asian countries, the studies of charcoal use in agriculture have
been mostly carried out by JICA (Japan International Cooperation Agency) experts.
In Indonesia, T. Igarashi started an experiment to produce rice husk charcoal
with a simple kiln and to cultivate soy bean and maize with the charcoal in
1989(14). Igarashi et al. (15) applied the charcoal together with magnesium phosphate
and lime respectively and tried to rotate soy bean with maize. The charcoal
application enhanced root nodule formation, plant growth and yields significantly.
The effect was also sustained in the second crop of maize without any supply
of fertilizers, and the residual effect was observed up to 10th rotation. In particular, the growth and yield of
maize treated with the charcoal were more than that in the control plot
cultivated only by chemical fertilizer. He also tried to apply the charcoal in
several areas with different soil condition and reported that the effect seemed
to be different according to the soil properties and the kind of crops (16). Since the publication of experiment results, charcoal
use is increasing in Indonesia.

In Thailand, Oka et al. (17)studied the effects of rice husk charcoal on the growth,
yield and nitrogen fixation rates of soy bean planted in an infertile sandy
soil. He reported that the amount of above ground biomass, root biomass, soy
bean yield and the rate of nitrogen fixation in soil increased significantly.
In field, the application of 10 ton per hectare was most efficient, and the
effect appeared evident in the second crop (sorghum) and the third (soy bean).
The soil physical properties, porosity, water holding capacity, pH and CEC were
also improved, although the changes varied with soil type.

In the Philippines, Noguti et al. (18) confirmed the effect of rice husk charcoal on the
growth of beans in an infertile acidic red soil. In this experiment rice
husk charcoal of 2.5 t / ha and lime of 1.5 t/ha were applied and mixed
with top soil, to 15 cm depth, chemical fertilizer was applied and the
root nodule bacteria inoculated. The number of root nodule and nitrogen
fixing rates increased in the plot with lime, but it was increased more
by the addition of charcoal. The inoculation of root nodule bacteria and
the application of rice husk charcoal induced the same effect with single
use of lime. Use of rice husk charcoal seems to be economic in the Philippines where the use of lime is rather costly for
farmers.

2) Wood and bark charcoal

In 1983, Ogawa et al. (4, 5) reported that the bark charcoal powders containing
a small amount of chemical fertilizers were efficient for the mycorrhiza
formation of pine tree and the A mycorrhiza and root nodule formations
of soy bean plant. In the experiments with soy bean plants (19), the bark
charcoal of broad leaved trees was mixed with 1 % (W / W) of the inorganic
fertilizer (N: P: K (8: 8: 8)), urea, super lime phosphate, ammonium sulfate
and oil cake powder respectively. These charcoal fertilizers were stocked
for one week and scattered over soil surface at 500 g / m2 and 1500g /
m2 each before plowing. Soy bean seedlings without root nodules were planted
in each plot. The plots in which inorganic chemical fertilizer was applied,
100 g / m2 and 200 g / m2 and control plots without any treatments were
established to compare the efficiency.

Soy bean yields harvested from the plots with
charcoal fertilizers of 500 g / m2 were mostly equal to those from the plots with
100 and 200 g of chemical fertilizer. By this method the amount of chemicals
could be reduced to 1/20th. Root nodule formation was stimulated by charcoal
fertilizers, but it was suppressed by the ones with ammonium sulfate and
synthetic chemical fertilizer. A mycorrhiza infection rates and the spore
numbers increased in the plots treated with charcoal fertilizers. It seems that
the better growth of soy bean plants resulted from the enhanced root growth and
propagation of symbiotic microorganisms being activated by the charcoal.

The soil microbial flora in each plot changed with
the application of charcoal fertilizers. Charcoal fertilizers with higher pH than
8 inhibited the propagation of soil fungi, but enhanced that of bacteria and
Actinomycetes soon after the treatment and then returned to the normal state
gradually. It was hypothesis that the emission of carbon dioxide increased
temporarily being caused by the high microbial activity. At the same time, the
free living nitrogen fixing bacteria could be isolated on the nitrogen free
medium. From the inoculation test of the charcoal which was sterilized and
buried in soil for a week, it was certain that the charcoal became the habitat
for root nodule bacteria (19).

The charcoal which was carbonized under high
temperature is usually alkaline and porous substance, and there is no substrate
for saprophytic microorganisms. When the charcoal was added into soil, at first
plant roots grow toward the charcoal with enough water and air. Next some microorganisms
which can endure under high alkalinity can propagate in or around charcoal. It
seems that the charcoal provides a better habitat for the root and symbiotic
microorganisms.

These research results were also confirmed in the TRA. Wood charcoal could
improve the soil properties, but mixtures with chemical fertilizers, zeolite,
wood vinegar and organic fertilizer exhibited better effects than charcoal
itself on tea plant, citrus and vegetables(20), rice plant
and apple tree (21) and some leguminous plants and grass for revegetation (22).

It was found that root nodule bacteria could often be immobilized with high frequency in white and hard charcoal with fine pores. So, Takagi (23) proposed the method to make the inoculum of root nodule bacteria of leguminous plants utilizing charcoal. On the other hand, A mycorrhizal fungi showed the better growth on black charcoal which was carbonized at 400-500 degree Celsius. The spore of Gigaspora margarita was formed in black volcanic soil with high carbon content (24). The application of wood charcoal to the plant associated with Frankia was effective also for the actinorhiza formation (25). In general, it is certain from these results that the white charcoal with fine pores and high pH is suitable for the immobilization of bacteria and the black one more suitable for fungi. After the study of TRA Oohira et al. (26) reported that the oak charcoal with finer pores than that of pine was more suitable for the immobilization of bacteria and Actinomycetes than that of pine. Meanwhile, the immobilizing ability of pine charcoal could be improved by mixing with acetic acid. Matsubara et al. (27)reported that coconut shell charcoal and the inoculation of A mycorrhizal
fungi were effective to suppress the infection of soil born pathogen Fusarium
spp..

These research results of charcoal use in
various fields were distributed not only in Japan but also in Asian countries mainly by Ogawa (28)
(29) (30).

3) Charcoal compost and wood vinegar

@@In Japan,compost making from litter and excretions has
been very common for a long time. Ash or carbonized material was an essential material
to accelerate the decomposition stimulating the bacterial activity and neutralizing
the acidity. It is also well known that the charcoal absorbs smell and liquid.

In 1980s, a private company Kingukouru invented the method to produce charcoal compost which was made from fresh chicken dung and pal shell charcoal (31). In the process of compost making, the more the charcoal
is used, the faster the decomposition progresses with exothermic reaction.
Under aerobic conditions the Bacillus group became dominant and produced
antibiotics. Kobayasi (32) reported that these antibiotics inhibited the
growth of some soil born pathogens, Pythium, Rhizoctonia, Phytophtra and
Fusarium and were effective to suppress root diseases of various plants.
At present the charcoal compost has been sold as a biological fungicide
by the company. Following this instance, various kinds of organic composts
have been produced from other livestock excretions and charcoal and sold
commercially.

It had been also well known that the liquid (wood vinegar) flowing out
of charcoal kiln was useful. It had been used in forestry nursery beds
as a pesticide and on road sides as a herbicide. Kishimoto et al. (33)
published a text book in which theyrecommended the use
of wood vinegar in agriculture, forestry, animal husbandry and food processing
describing the methods for purification, distillation and filtration.

Wood vinegar is a byproduct which is obtained from
the carbonization process by cooling the smoke with air or water. This liquid
contains the volatile substances emitted with pyrolysis; the water soluble fraction
is wood vinegar and the oily one is wood tar. The chemical composition is
different depending on raw materials. Major components of broad leaved trees
are 81 % water, acetic acid 8-10 %, methanol 2.44 %, acetone 0.56 % and soluble
tar 7 %, and that of conifers are rich in water, acetic acid 3.5 % and the
others concentrations are lower than that of broad leaved trees (34). The
chemical components of wood vinegar containing many organic substances are
unstable, so it has been sold as the material complex.

It has been recognized since 1960s that the
wood vinegars extracted from broad leaved trees are more efficient for the
growth and rooting of various plants than that of conifers. The effects were
confirmed also in the study of TRA (35) (36) (37). The concentrated liquid of
wood vinegar with strong acidity can kill microorganisms, plants and some
larvae, but the diluted form stimulates rooting, plant growth and microbial
propagation. There are many reports of the application in field
practice and generally the effects have been well known by users, but there are
a few available scientific reports on the mechanisms associated with the
chemical properties.

2. Utilization in Forestry and Revegetation

1)Rehabilitation and reforestation of trees and pine
forest by charcoal and mycorrhiza

In 1980, Ogawa et al. (38)tried to apply the bark charcoal powders with a small amount of chemical
fertilizers and succeeded to promote the growth of pine, Pinus thunbergii
and cultivate the mycorrhizal fungi, Rhizopogon rubescens which is a dominant
mycorrhizal species in the young stand with infertile basic sand

Some chemical
fertilizers, urea, ammonium sulfate, super lime phosphate and synthetic
chemical fertilizer, were added to bark charcoal powder with 0.1-1.0% (W / W)
respectively. These materials were buried into the trenches 30 cm in depth and
width after cutting the roots and then covered with sand. The regenerated fresh
roots grew inside the charcoal layers vigorously after 3 months and the
mushrooms appeared abundantly along the trenches 9 months later. After a year,
the amounts of pine root and mycorrhiza increased considerably in the charcoal layers.
In addition, the growth of shoots and the color of needles became better than
before treatment. These apparent effects probably resulted from the regeneration
of roots and the formation of mycorrhiza. It might be caused from the enhanced nutrient
uptake and the water absorption through mycorrhiza. The water content in the
charcoal was remarkably higher and it was kept at 40 % even in mid summer
comparing with 5 % outside the charcoal layer (39).

After publishing the experiment results, similar
phenomena were confirmed by many researchers in local forest experiment
stations, because it is an edible mushroom in Japan. For example, Hirasa (40)devised
the growing method of seedling with the mycorrhiza and the field cultivation
method.

The same method has been widely accepted by
professional gardeners and applied to various kinds of tree species to revive
famous old trees in shrines, temples and parks. Usually the charcoal powder,
maximum 1 cm in diameter, has been buried in trenchs or holes together with a
small amount of phosphate fertilizer and the spores of suitable mycorrhizal
fungi to host plant. Sometimes the root system was exposed removing top soil
and covered by charcoal powder as well. Also in nurseries, the charcoal
fertilizer is mixed with pot soil to improve soil properties and inoculate the
mycorrhizal fungi (41).

Both pine wilting disease by the insect and
nematode and oak wilting by the insect and fungi have been spreading mainly in
western Japan for several decades, and now it has become very serious problems in forestry.
Pinus densiflora forest in low land has mostly disappeared in the southwest
and reaches to northern most area of Honshu. Pinus thunbergii forest which had been planted along the seacoast to
prevent natural disasters was also declining. Therefore, the practical
methods of the rehabilitation and reforestation of pine forest have been
eagerly expected in rural areas.

Mycorrhiza formation is essential to Pinus species which generate the forests
as a pioneer plant at dry sites with infertile soil. These fungi also prefer
to propagate in dry and infertile soil conditions. Therefore, it has been
well known through the ecological study of pine forest (2) that the man-made
pine forest should be kept at the primary stage of plant succession by
cutting all of under shrubs and raking out the litter layer.

M. Ogawa proposed to rehabilitate and reforest the coastal pine forest
using charcoal and mycorrhizal fungi publishing a monograph (41). In the
established forest, the same methods described previously have been applied.
Meanwhile, in a place from which all of pine tree were destroyed, the under
shrubs and top soil must be completely removed before planting. Then pine
seedlings with the inoculated mycorrhizal fungi, Rhizopogon, Pithoritus,
Suillus species, are planted together with the charcoal powder. The survival
rates of these seedlings were much higher than that without mycorrhiza
and charcoal.

As such
a trial, growing tree and burying charcoal, seems to be one of the practical
methods for carbon sequestration, Ogawa M. and his colleagues have promoted the
movement to make revive gWhite Sand and Green Pineh which is one of the
symbolic scenery of Japan islands in order to contribute the prevention of
natural disasters and the countermeasure for global warming.

M. Ogawa who was working in the rehabilitation project of tropical rain
forest in 1989 found that a dominant species, Dipterocarpaceae, forms the
ectomycorrhiza with several fungal species among which Scleroderma columnare
enhanced the seedling growth efficiently in nursery. He tested the effect
of charcoal powder on the growth of Shorea species and found that the small
amount of charcoal 2 % in volume was effective to stimulate the mycorrhizal
formation and the growth(42). Kikuti J. and M. Ogawa (43) devised the practical inoculation method
in which several saplings with the mycorrhiza were planted inside the nursery
beds and the pots were set under the canopy. By this method the mycelium
of mycorrhizal fungi penetrates through holes of the pot and naturally
infected. Mori et al. (44) found rice husk charcoal is also effective and
established the more convenient method. Rice husk charcoal is not so harmful
even if it was added excessively.

The nursery technique to inoculate the
mycorrhizal fungi with charcoal was also used in the forestation project of
pine in northern China and obtained successful results (45). The material such as charcoal which has higher water holding capacity is efficient to stimulate the rooting and to supply water to the root through mycorrhiza even under severe dry condition. It can be expected the charcoal will be used in dry land farming like date palm plantation and the revegetation to stop desertification (46).

3.Utilization of charcoal and wood vinegar in animal husbandry and
fishery

Charcoal powder had
been commonly used to cure the intestinal disorders of animals. In 1980s the
utilization of charcoal and wood vinegar extended into the fields of animal
husbandry and the fish aquaculture. In the 1970fs one of the wood vinegar makers invented a tablet of charcoal
powder containing wood vinegar and sold as a medicine for livestocks ; this was
formally recognized by MAFF (33). When animals take the drug with the feed, it
is said that the quality of meat, fat and egg can be improved because of effect
on activity of intestinal microorganisms (47). Recently the use for pig and
poultry increased to avoid antibiotics and to prevent epidemics.

In general, charcoal powder has the strong
ability to absorb the smell of excretions and liquid. The charcoal carbonized
under lower temperature than 300 degree Celsius especially shows the strong adsorption
of ammonium(48). The mixture of charcoal and wood vinegar has been used
in barn of housed livestock as the deodorant and absorbent of liquid. It seems
that these effects result from the complex reactions of charcoal and wood
vinegar, but there has been little available scientific investigation (33).

The material containing wood vinegar also is
used in the aquaculture of eel and fish to keep water clean (33). Sometimes high
quality charcoal which is carbonized under higher temperature has been also used
for water purification in the fish tank. From experiences it is said that fish
likes to spawn around the charcoal, probably because some algae propagate on the
wood charcoal and carbon fiber

4.Trials of carbon sequestration
by charcoal use in agriculture and forestry

1)Developing charcoal industry

In 2000, the
fundamental law concerning the establishment of a recycling social system was
enacted in Japan, and it was required
to reuse any wastes as much as possible. The incineration of waste woods was particularly
prohibited in order to reduce the discharge of CO2 and dioxin. The total amount
of waste woods mainly from construction has reached to 4.6 million ton per
year, but the domestic use is only 60 % still now. Therefore, some construction
companies have switched from incineration to carbonization and intended to use
the charcoal not only in agriculture but also for the humidity control of houses
and buildings, because it is necessary to reduce the high humidity of buildings
in Japan.

The function of
charcoal for humidity control was studied intensively several decades ago (49)
(50). Recently the construction companies have begun to spread the charcoal bag
not only over the under floor but also above the ceiling (51). Meanwhile it was
also reported that the treatment was efficient to reduce asthma and atopic dermatitis
by diminishing the population of molds and ticks (52) (53).

With the development
of charcoal utilization, carbonization technology is developing from the simple
kiln to the automatic mass production facilities. The newly devised carbonizers
including various kinds of movable batch type kiln, rotary kiln, swing kiln and
etc has been sold for the mass production of waste wood charcoal. In some cases
the extra gas has been used for thermal electric power generation. At the same
time, the studies to establish the industrial standards and function of
carbonized materials have started, and the charcoal industry begins to be renewed
in the 21st century.

2)New materials of charcoal

Recently the raw
materials of charcoal are ranging from waste woods to some flammable substances.
Among them the carbonization of bamboo and its utilization has been widely
noticed as one of the management methods of bamboo forest which occupies wide
ranges in southwest Japan. Bamboo charcoal with
somewhat different structure and functions from wood charcoal has been used for
the purification of water and air.

Up to several years ago, all of garbage from urban life had been burned in incineration plants, but now some cities began to carbonize the garbage and try its utilization. But there are some problems to be solved, because the water content is usually so high that it consumes too much energy for desiccation, and some products are unsuitable for agricultural use because of the high concentration of heavy metals and salt (54). Therefore, the thermal electric power plants have tried to burn the garbage charcoal mixing with coal and oil (55). The wastes disposed from food processing and live stock excretions have been also carbonized and used in agriculture with compost (55).

3) Carbon Sequestration by Forestation
and Carbonization (CFSC)

On January 8 in 1991, M. Ogawa puts forward a
new idea gThe earthfs green saved with charcoalh writing an article in Nihon
Keizai Shinbun (Nikkei). He described in this paper the outline of this concept;
The carbon dioxide emitted into air can be fixed by photosynthesis into the
planted tree; If the waste wood will be carbonized and used in agriculture and
other fields, a vast amount of carbon will be stored for a long term in soil,
and at the same time sustainable production of crops and trees will be achieved.

In 1990s it has been recognized gradually in
Japan that the carbonization are meaningful as a counter measure against global
warming through the production of renewable energy and the uses for soil
amendment in agriculture. However, the raw materials of carbonization in this
project must be restricted only the plant residues, because it induces large
scale deforestation as well as other biomass energy productions.

After COP3 (The 3rd
Session of the Conference of the Parties to the United Nations Framework
Convention on Climate Change), Ogawa (56) (57)proposed the idea gCarbon
Sequestration by Forestation and Carbonization (CSFC Project)h in Japan and Asia. In Indonesia and Malaysia, the large scale plantations of Acacia mangium for paper pulp and that
of oil palm for biomass energy are expanding after clear cutting of the
natural forests. Fast growing species in monoculture has been cut in rotation
of every 8 to 10 years, and still now the slash burn fields are also spreading
over wide area. The sustainability of tree plantation and cropland in tropical
region has always become very serious problem. It needs to develop more
efficient techniques for soil amendment to sustain the high productivity.
It is certain that the charcoal use is one of the most reliable and low-cost
procedures being harmonized the nature. The same opinion was proposed in
the review written by Glaser et al. (58).

If charcoal is easily
weathered (oxidized) in field, the idea may be meaningless. But it has been actually
exhibited that the charcoal has remained for one thousand years or more without
weathering at the ruin of ancient coin studio and in the old tombs in Japan and Korea.

After the observation of stability in sulfuric acid, sodium hydrate or
under ultra violet light for short term (personal communication), Kawamoto
et al. (59) examined the durability of wood charcoal against ozone and
estimated the half-life of the charcoal in air. The weight of saw dust
charcoal carbonized at 400oC was not affected with 8.5% ozone, while the
one done at 1000oC burned with 4.9% ozone. There were observed minute pores
on the surface of charcoal carbonized at 1000oC. The half-life of charcoal
which was carbonized at 1000oC and treated by ozone in air was about 50,000
years. From these results it is suggested that wood charcoal is stable
on a geological time scale.

On the other hand, Yamato et al. (60)reported the changes in soil chemical properties and the crop yields when
the bark charcoal of Acacia mangium, which was made of waste from pulp
industry, was applied as soil amendment for the cultivation of maize, cowpea
and peanut in Sumatra, Indonesia. The yields of maize
and peanut significantly increased after the application of bark charcoal under
the fertilized condition in an infertile soil. The amount of root and the
colonization rate of A mycorrhiza increased especially in maize. The
application of charcoal improved the soil chemical properties by neutralizing
soil pH and increasing total nitrogen, available phosphate contents, cation
exchange capacity, amount of exchangeable cations and base saturation. Moreover,
it induced the decreasing of exchangeable Al ion which seems to be harmful for
the root growth. The effects of charcoal application appeared more evidently in
tropical region than those in Japan. Root nodule
formations of leguminous plants were also stimulated by charcoal.

Formerly it was reported
that the population of free living nitrogen fixing bacteria increased around
the charcoal buried in tropical soil (28).Probably a small amount of
nitrogen seems to be accumulated into soil by charcoal application also in
slash burn cultivation.

According to these
results in Indonesia, the feasibility study of CSFC project was conducted with the existing project of an industrial plantation and pulp production by Okimori et al. (61) in Indonesian Sumatra as an example of Clean Development Mechanism (CDM) project. It was prospected that a total of 368,000 t / year of biomass residue and waste which were disposed from plantation and pulp mill could be transformed into charcoal of 77,000 t / year, if conventional charcoal producing methods are used. It was also expected that the carbon emission reduction by the project reaches to 62,000 t-C / year (or 230,000 t-CO2). In addition, this project can contribute to local economy providing the employment chance for 2,600 people, and will realize sustainable industrial plantation by soil amendment with charcoal.

A similar trial was conducted also in Indonesian JICA project as a small scale example, and the research result was reported by JICA (62). In this project it was confirmed that the applications of charcoal were effective both for the seedling growth of Acacia and tree growth in field.

In Western Australia, the multipurpose
project of mallee eucalyptus plantation has been carried out by Oil Mallee
Company and Shea (63)in order to prevent the salinization of arable soil. Another feasibility
study of the project was conducted by Ogawa et al. (64)in West Australia joining to the existing project. They proposed to carbonize wood waste
and to use the charcoal for soil amendment in wheat field. In this study,
it was prospected that the total carbon sink would reach 1,035,450 Mg-C
with 14 % by aboveground biomass, 33.1 % by belowground biomass and 52
% by charcoal in soil, if the plantation will be kept for 35 years. Meanwhile,
the effects of eucalyptus leaf and stem charcoal on the growth and yield
of wheat were identified by Blackwell et al (65).

she feasibility study of carbon sequestration in which various kinds of waste wood out of construction, saw mill, trimmed branch and others were recycled by carbonization was conducted by RITE (Research Institute of Environment and Industry) as summarized in the previous paper(64). It was focused on the effective use of surplus heat from a garbage incinerator for carbonizing woody materials. It was prospected from the study that the waste wood of 936.0 Mg-C / year would be converted into the net carbon sink of 298.5 Mg-C / year by carbonization, with the fixed carbon recovery of the system being 31.9 %.

The life cycle
assessment has been conducted also in Japan on the case of
carbonization of waste wood and the use of charcoal for construction and revegetation.
By this study it was certified that the CSFC project is significant and useful
for carbon sequestration also in carbon and energy balance (Senoo and Kosaki unpublished).

From these research
results, it is expected that CSFC project will be recognized as a concrete,
easy and low cost counter measure when the global warming will intensify more
seriously in the near future. Today the charcoal uses in various fields are
extending through the release of technical information, and the charcoal production
industry is growing as one of the environment businesses not only in Japan but also among Asian
countries.

(6)Technical Research Association for Multiuse of Carbonized Materials(TRA)
ed. (1990) gThe Research Report on The New Uses of Wood Charcoal and Wood
Vinegarh Technical Research Association for Multiuse of Carbonized Materials
Tokyo pp. 374 (in Japanese)

(54) Abe I. et al. (2001) gCarbonization of all wastes ,urban wastes,
sewage, garbage and waste woods, and their utilizationh Proceedings of
the symposium on the production of charcoal and activated charcoal from
wastes and their utilization. pp. 294, NIS Inc. (in Japanese)